1. Field of the Invention
The present invention relates generally to an intervehicle distance control system for vehicles. More particularly, the invention relates to an intervehicle distance control system for vehicles having accelerator means to which operation is imparted by a reaction force of a strength corresponding to the possibility of collision between a vehicle in question and an interfering object disposed in the path of travel of the vehicle.
2. Description of Relevant Art
There have already been known various intervehicle distance control systems for vehicles wherein the distance between a vehicle in question (i.e., one provided with such a system) and an interfering object disposed in the path of travel of the vehicle, and the relative speed therebetween, are measured by means of radar or the like, and a braking operation is automatically applied to the vehicle in question on the basis of a comparison between values thus obtained and reference values, to thereby avoid collision with the object.
In such conventional automatic braking type intervehicle distance control systems, however, when there has arisen a difference between a uniform judgment of a braking signal generating processor and a collision avoiding scenario pictured in the driver's mind on the basis of his perception and experience, in the interest of safety priority has in many cases been assigned to the processor's judgment. Consequently, such conventional systems require improvements in consideration of vehicles located behind the vehicle in question, or from the standpoint of the driver's mental well-being.
In view of the foregoing, there has been proposed, in U.S. patent application Ser. No. 309,018 filed on Oct. 6, 1981, an intervehicle distance control system for vehicles wherein an operation reaction force of a strength corresponding to the possibility of collision between a vehicle in question and an interfering object in the path of travel of the vehicle is imparted to accelerator means in the form of a throttling pedal. The driver is thereby made aware of the possibility of collision, while the selection of accelerator operation is substantially left to the driver's discretion.
However, even the aforesaid acceleration reaction force type intervehicle distance control system still has room for improvement in the following respects. Such control system utilizes a pulse motor or oil pressure as means for generating the acceleration reaction force. In the case of a pulse motor, an artificial displacement, once analogously produced thereon, is converted to a force through a spring, so that the spring constant of the spring is normally fed back to the stroke of the throttling valve and, as this pedal is depressed through a stroke thereof by the driver's foot, the reaction force will increase even when the system is not in operation, which may result in a mental burden on the driver during high-speed driving. On the other hand, in the case of utilizing oil pressure, the provision of an exclusive hydraulic pump is an additional requirement, so that the system becomes more complicated and larger in size. Further, the pump driving power is remarkably large, and consequently the system tends to be less economical. In such an oil pressure type, moreover, a sufficiently light feeling of the accelerating operation is sometimes not obtainable because of the designing of such system to require the driver to sense by feeling the piston sliding resistance at the cylinder portion by way of the pedal.
The present invention effectively overcomes the above described problems attendant the aforesaid acceleration reaction force type intervehicle distance control system.